Breast cancer is a cancer which occurs in mammary gland tissues and is classified into lobular carcinoma arising from acinus and breast ductal carcinoma arising from breast ducts. The state of cancer limited within lobules or breast ducts and not disseminating to surrounding tissue is called noninfiltrating cancer whereas the state in which cancer cells proliferating in breast ducts destroy basement membrane and develop metastasis to the neighboring tissues is called infiltrating cancer. As a treatment method for breast cancer, adjuvant chemotherapy is common, in which an anticancer agent is administered by instillation after surgery operation for excising affected parts or without surgery operation. However, many of anticancer agents have problems that they may cause side effects such as nausea, loss of appetite and alopecia when administered by instillation.
Meanwhile, it has been reported that activities of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) increase upon the development of breast cancer (Non-patent Documents 1 to 5). Furthermore, it is known that non-steroidal antiinflammatory analgetic agents are effective for inhibiting COX-1 and COX-2.
Mastitis is classified into stagnation mastitis and acute suppurative mastitis. Stagnation mastitis develops just after the puerperium in the state that milk stagnates within breast ducts. On the other hand, acute suppurative mastitis develops by infection of bacteria such as staphylococcus, Escherichia coli and streptococcus. Of these, treatment with an antiinflammatory analgetic agent is performed for acute suppurative mastitis (Non-patent Document 6).
However, there has been a problem that non-steroidal antiinflammatory analgetic and/or anticancer agents cannot be administered topically since breast cancer and mastitis occur or develop within the breast.
As attempts to treat breast diseases such as breast cancer by topical administration of a medicinal agent, methods of percutaneously administering adriamycin, danazol or progesterone to the breast have been reported (Non-patent Document 7, 8 and Patent Document 1).    [Patent Document 1] WO2004/060322 (Description)    [Non-patent Document 1] Igaku no Ayumi (Journal of Clinical and Experimental Medicine), 204 (1), 10-19, 2003    [Non-patent Document 2] Journal of the National Cancer Institute, 90 (21), 1609-1620, 1998    [Non-patent Document 3] Journal of Cellular Physiology, 190, 279-286, 2002    [Non-patent Document 4] Annual Reviews Medicine, 53, 35-57, 2002    [Non-patent Document 5] Carcinogenesis, 23(2), 245-256, 2002    [Non-patent Document 6] Shusanki Igaku (Perinatal Medicine), 34 (9), 1443-1445, 2004    [Non-patent Document 7] Yokohama Igaku (Journal of Yokohama Medical Association), 44, 487-494, 1993    [Non-patent Document 8] Dermatology and Venereology, V(2), 65, 1951